Field of the Invention
This invention relates in general to a method of suppressing polarization-dependent loss in a signal, and in particular to a method of suppressing the effect of polarization-dependent loss in a signal in an analog, polarization-modulated, RF photonic optical link.
Description of the Related Art
The use of polarization modulators (“PolM”) in analog optical links has been made possible with the advent of reliable modulators with modest Vz voltages and the ability to apply separate DC-controlled static biases. PolMs have been demonstrated for a variety of applications of photonic links, such as orthogonally polarized single-sideband modulator, intensity noise suppression, third order distortion suppression, frequency doubling optoelectronic oscillator, and photonic analog-to-digital convertor applications.
Common impairments of such analog optical links employing PolMs include chromatic dispersion, photodiode distortion correction, and/or polarization-dependent loss (“PDL”). Of these, PDL is a dominant impairment of PolM links because it creates unintentional intensity modulation in the same manner as the detection process.